Video report by ITV News Correspondent Sejal Karia
Sasha Johnson, both a BLM activist and senior member of the political party, Taking the
Initiative Party (TTIP), was injured in the early hours of Sunday in South London.
The political group TTIP said the mother of two had received "numerous" death threats because of her activism.
However, a friend of the activist has said she believed the incident was "more related to rival gangs".
Imarn Ayton, who met Sasha Johnson during the Black Lives Matter protests last year, told ITV News Ms Johnson had been at a party when she was injured but she "does not believe she was the intended victim".
"I do believe that it was a party and there was some type of dispute between two individuals or two gangs, and it was wrong place, wrong time."
"I do not believe that she was the target," Imarn Ayton tells ITV News
Ms Ayton said: "And the third-party information that I have received also alludes to the fact that she wasn't the target."
She added: "I was just so shocked, I'm still shocked to be honest with you, it's very surreal and honestly I'm just so heartbroken for her family."
Ms Ayton said: "I can’t speculate, I wasn’t there. Again, just based off of the information that I’ve been given from closer friends and family, as far as we are aware, she was at a party or some sort of gathering and this incident is more related to rival gangs as opposed to her activism, let’s just say that."
'Sasha's political party believe she was brutally attacked', ITV News Correspondent Sejal Karia reports
Ms Ayton continued: "I think it’s more to do with gangs or gang violence or rivalry or some type of dispute between two different groups, and the incident was not intended for Sasha as far as we are aware, as I am being told by closer friends and family."
She added: "There was a rival gang that may have heard about someone being in that party that they didn’t feel quite comfortable with or trusted and so they resorted to driving past and shooting into the garden, and one of those shots obviously hit Sasha Johnson.
Her comments come a day after the TTIP said on Instagram: "It is with great sadness that we inform you that our own Sasha Johnson has been brutally attacked and sustained a gunshot wound to her head.
"She is currently in intensive care and in a critical condition. The attack happened in the early hours of this morning, following numerous death threats as a result of her activism.
"Sasha has always been actively fighting for black people and the injustices that surround the black community, as well as being both a member of BLM and a member of Taking the Initiative Party’s Executive Leadership Committee.
"Sasha is also a mother-of-two and a strong, powerful voice for our people and our community."
The Met Police said the woman was found after officers were called to reports of gunshots in Consort Road, Peckham, south-east London, shortly before 3am.
It is believed the shooting occurred in the vicinity of a house where a party was taking place and a number of people may have been in the area.
A spokesman said that while the investigation is at an early stage, there was nothing to suggest it was a targeted attack or that the woman had received any credible threats against her before this incident.
Detectives from the Met’s specialist crime command (Trident) are leading the investigation.Detective Chief Inspector Jimi Tele said: “This was a shocking incident that has left a young woman with very serious injuries. Our thoughts are with her family who are being provided with support at this terribly difficult time.”
He said detectives are making “good progress” in hunting the attackers but they need help from the public.
It is “crucial” that anyone who saw anything suspicious in the Consort Road area in the early hours of Sunday or who has heard information since then get in touch.